[Buildroot] [RFCv3 14/15] Makefile: evaluate CCACHE and HOST{CC, CXX} at time of use

[Yann E. MORIN <yann.morin.1998@free.fr>]

Thomas, All,

On 2017-12-01 21:53 +0100, Thomas Petazzoni spake thusly:
> As we are going to move to per-package SDK, the location of CCACHE and
> therefore the definitions of HOSTCC and HOSTCXX need to be evaluated
> at the time of use and not at the time of assignment. Indeed, the
> value of HOST_DIR changes from one package to the other.
> 
> Therefore, we need to change from := to =.
> 
> In addition, while doing A := $(something) $(A) is possible, doing A =
> $(something) $(A) is not legal. So, instead of defining HOSTCC in
> terms of the current HOSTCC variable, we re-use HOSTCC_NOCCACHE
> instead.
> 
> Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

Reviewed-by: "Yann E. MORIN" <yann.morin.1998@free.fr>

Regards,
Yann E. MORIN.

> ---
> Changes since v2:
>  - New patch
> ---
>  Makefile | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/Makefile b/Makefile
> index d8fa91120b..e05a1ec09a 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -446,11 +446,11 @@ BR_PATH = "$(HOST_DIR)/bin:$(HOST_DIR)/sbin:$(PATH)"
>  TARGET_DIR_WARNING_FILE = $(TARGET_DIR)/THIS_IS_NOT_YOUR_ROOT_FILESYSTEM
>  
>  ifeq ($(BR2_CCACHE),y)
> -CCACHE := $(HOST_DIR)/bin/ccache
> +CCACHE = $(HOST_DIR)/bin/ccache
>  BR_CACHE_DIR ?= $(call qstrip,$(BR2_CCACHE_DIR))
>  export BR_CACHE_DIR
> -HOSTCC := $(CCACHE) $(HOSTCC)
> -HOSTCXX := $(CCACHE) $(HOSTCXX)
> +HOSTCC = $(CCACHE) $(HOSTCC_NOCCACHE)
> +HOSTCXX = $(CCACHE) $(HOSTCXX_NOCCACHE)
>  else
>  export BR_NO_CCACHE
>  endif
> -- 
> 2.13.6
> 

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